Project I am working on

[diablocanyon1]

I am modifying a device. Currently, it is very simple. It has an RPM control and an electric motor and runs on AC power.

I wanted to know how I could go about making it so that the motor runs for a certain amount of time after pushing a button then shuts off automatically until the button is pushed again.


Thanks for your help.

 

[mneary]

I wanted to know how I could go about making it so that the motor runs for a certain amount of time after pushing a button then shuts off automatically until the button is pushed again.

You use a timer circuit to enable the RPM control.

 

[Sceadwian]

Post schematics for what you have already.

 

[diablocanyon1]

You use a timer circuit to enable the RPM control.

I am aware of that. I should have been more clear.

The motor makes a plate oscillate back and forth. I would like the motor to stop once the plate returns to its equilibrium position. The timer would work if I always used the same RPM setting. However it would be thrown off if I inc. or dec. the speed.

 

[arrie]

How do you increase or decrease the rpm.
That same device could be used to adjust your timing on your timer.
You would then require some software control for that process, so maybe a mcu, some A/D, who knows, you might just come right.

Depending on how you increase or decrease the rpm.

 

[Sceadwian]

You need some other kind of feedback, like a zero cross detector. Something like an SCR might work as the SCR won't stop conducting until the next current zero cross even if it's gate signal is removed. You really need to supply more details.

 

[crutschow]

The motor makes a plate oscillate back and forth. I would like the motor to stop once the plate returns to its equilibrium position. The timer would work if I always used the same RPM setting. However it would be thrown off if I inc. or dec. the speed.

Can you detect the position of the plate with some type of limit switch at the equilibrium position? If so, just connect the limit switch in series with the motor to stop it. The push button would be wired in parallel with the limit switch to start the motor for the next cycle.

This setup, of course, would work independent of speed.

 

[HSM1986]

if u used timer 555 IC and it's output let it enter AND IC with a sensor that sense the motor when it's get to it's equilibrium position.
just an idea that came to my mind..